1. Field of the Invention
This invention pertains to compression tools and more particularly to hand operated compression tools adapted for exerting a large compression force.
2. Description of the Prior Art
A number of hydraulic compression tools have been developed for compressing metal connectors about electrical conductors to form an electrical and structural connection between two conductors, or between a conductor and a terminal. When two conductors are connected, each conductor end is inserted into an open end of a connector. The connector is then exteriorly compressed by the hydraulic compression tool to mechanically lock the conductors to the connector and to establish electrical continuity between them.
There are currently many types of connectors in use. One type commonly used is of a cylindrical configuration, called a sleeve connector, which will connect two conductors together in a straight line. A variation of this type provides a cylindrical section with a flat portion for connection of a conductor to a terminal. Another type of connector in common use is of an "H" type design, called a parallel tap connector, which has two, parallel open sections. A conductor is inserted in each open section and then, by compression, the open ends of the connector are closed and locked over the conductors by the compression tool. The McDurmont U.S. Pat. No. 3,154,981 and the Campbell, et al U.S. Pat. No. 4,350,843, illustrate a prior art hydraulic compression tools. Further examples of prior art hydraulically operated tool heads are disclosed in U.S. Pat. Nos. 2,821,877, 3,230,713, 4,136,549, 2,688,231, 2,254,613, 3,417,599, and 2,696,850.
Some compression tools which compress cylindrical connectors utilize a plurality of opposed, pointed, nibs which are urged towards a common center as the levers of the tool are operated. Each of these nibs compress a portion of the connector onto the conductor ends. Other compression tools use opposing "C" shaped dies which are urged towards one another to compress the connector to the conductor. These types of tools may be used on both cylindrical and "H" type connectors. For "H" type connectors the curvature of the dies act to fold the open positions of the connector over the conductor thereby closing the connector over the conductor and locking the connector to the conductor.
Generally, tools designed to accept the "C" shaped dies for the "H" type connectors will compress only a limited range of cylindrical connectors. Also, tools having the opposing, pointed nibs will not fold the open portion of an "H" type connector over the conductor to satisfactorily lock the connector to the conductor. Thus, one disadvantage of the prior art was that the use of cylindrical connectors generally required the use of a particular type of compression tool to achieve the appropriate connection. The use of an "H" type connector required the use of another type of tool. If both cylindrical and "H" connectors were required on a job, two separate types of compression tools had to be used.
There are also many different conductor diameters in use. Generally, the diameter or size of a connector will correspond to the conductor diameter to which it is to be joined. In the past, some compression tools required the use of interchangeable dies of varying sizes to accommodate different sizes of connectors. Other tools could only crimp specific sizes of connectors and different tools would have to be used for varying sizes of connectors.
One disadvantage in using a tool that requires varying sizes of dies is that many times a particular die size is lost or not available for the connector size to be compressed in the field. This renders the tool useless for that particular compression connection. Another disadvantage in changing dies for each change in connector size or in changing tools for changes in connector size is that such changes are time consuming and increase the job time where multiple connections are being made on varying sizes of conductors. Thus, traditional compression tools required that a separate inventory of tools and dies be kept on hand in the field. Each time a connector size is changed the lineman must determine which tool or which die size is proper for the intended connection.
In view of the above disadvantages, there is a need in the field for a tool which will accommodate both cylindrical connectors and "H" type connectors. Further, there is a need in the field for a compression tool which uses a minimum number of dies to compress a maximum variety of connector sizes. Also, there is a need for a compression tool which is easily and quickly convertible from use on cylindrical connectors to use on "H" type connectors and vice versa, where such conversion can be made in the field and without substantial modification to the tool.